The incidence of skin test positively for 48 allergens have been evaluated in children with bronchial asthma. We studied the 347 cards of clinical file the allergic children a course 32 months. The most frequent allergens is Dermatophagoides pteronyssinus, cat and the other 24 allergens were less 10%. This allergen appears to present in Mexico Valley, the incidence to this allergen might be considered must frequent in allergic children who do reducing skin test for diagnostic allergic diseases.